Broadcasting

7. Broadcasting

Any packet (message) entering the MORSE network can be labelled as a
broadcast one. Either the user labels selected packets, or it is possible
to set labelling of all packets coming through the user part of the
respective CNI (Channel to Node Interface). Once a broadcast packet enters
the network, it is spread around following (B)c menu settings
of all the nodes that receive it.

With careful settings in all network nodes it is possible to achieve
the ultimate goal of broadcasting – to deliver a message simultaneously to
all network members – even in large networks with a complex
architecture.

When a broadcast packet is transmitted in the RF channel, every
receiving CU delivers it to the respective node (to all 5 nodes in radio
part). There it is checked for the source address first. If the source
address corresponds with the node settings (src base & mask), the
packet is multiplied and delivered simultaneously to different node
outputs according to the (B)c menu settings.

For example, let us have the user and net node outputs switched on.
The received (and checked) broadcast packet is then delivered to the user
channel and simultaneously to the retranslation network channel. The
latter is typically the RF channel, so in this example the packet will be
transmitted on the RF channel again. Using the configuration described
above, even broadcast packets can exploit store-and-forward repeaters. Of
course an effective algorithm for discarding repetitive packets is
implemented.

— Only masked parts of the (s)ource base addr and
the packet source address are compared

(u)ser output: ON

— Switch for sending a packet copy to the user output of the
node

(l)ink output: OFF

— Switch for sending a packet copy to the retranslation link
output of the node

(n)et output: ON

— Switch for sending a packet copy to the retranslation net
output of the node

(N)ode ID: 255

— Switch for sending a packet copy to the next node within the
same CU (No.0 to No.4, whilst 255 means no next node).

next (a)dr: 690F0003

— When a broadcast packet is sent to the retranslation net
output, this address denotes the node from which the acknowledgement
will be expected (this is used for secured transfer of a broadcast
packet between repeaters on an RF channel). Next(a)dr:0
means no acknowledgement will be expected (unsecured
transmission)